The invention relates to telephone communication devices and more particularly to a device which allows handicapped persons to communicate with anyone over a standard telephone network.
Previously, communications methods used by those with speech and/or hearing handicaps included teletype, telegraphic devices, sign language or written messages. Teletype devices are standard equipment connected to a telephone system by means of a modem. Telegraphic devices utilize either a sound-activated switch or a frequency detector connected to a light or vibrator which is activated in response to a signal which may be conveyed over a standard telephone circuit. This allows a message to be transmitted in a code such as Morse Code. Sign language for the deaf is a form of manual communication where the position and movement of the hands and fingers or gestures represent characters or words. This is used for face-to-face communication or communication by means of television signals which can be transmitted at radio frequencies or over telephone lines. For the uninitiated, written messages are the simplest form of communication. This involves writing out a message and passing the pen and paper back and forth in face-to-face communication.
All of these prior devices have disadvantages. Teletypes are large, heavy, and expensive. They can be used to communicate only with another compatible teletype. Furthermore, teletype systems cannot communicate with any telephone or with a person who does not have a teletype connected to his phone.
Telegraphic devices are also limited to use with a similar device and further require the memorization of Morse Code or other complicated codes. They are also subject to interference by noise, are slow, and are difficult to use, requiring a degree of manual dexterity.
Learning the deaf sign language is time consuming; it requires good manual dexterity, good vision, rapid interpretation, and the memorization of more than 800 signals. Furthermore, it is easily misunderstood and may only be used within visual range or over expensive television circuits.
Finally, written messages are slow, awkward, and require pencil and paper. This technique cannot be used over standard telephone circuits without the use of elaborate television equipment.